Detergent compositions



3,037,937 DETERGENT COMPOSITIONS Jay C. Harris, Dayton, Ohio, assignor to Monsanto Chemical Company, St. Louis, Mo., a corporation of Delaware No Drawing. Filed Nov. 21, 1956, Ser. No. 623,519

12 Claims.

The present invention relates to novel detergent compositions and methods of washing metallic objects containing copper, such as cutlery in order to avoid tarnishing cutlery.

It is known that certain metals and alloys, especially those containing copper such. as German silver or brass, or plated objects containing such alloys become objectionably discolored, tarnished or corroded when contacted with solutions containing synthetic detergents.

It is an object of this invention to provide improved detergent compositions containing an inhibitor which is eifective to prevent such discoloration.

According-to the present invention there are provided detergent compositions containing organic nitrogen compounds having the formula:

CNX y H H2CN in which X is an alkyl radical having from 4 to 24 and preferably from 14 to 22 carbon atoms. Examples of "compounds having the above formula are l-(fi-hydroxyethyl)-2-(gamma-ethyl amino)-,2-imidazoline, l-(fi-hydroxyethyl)-2-(gamma-propyl amino)-2-imidazoline and 1-(fi-hydroxyethyl)-2-(gamma-butyl amino) 2 imidazoline as representative of lower members of the series or 1-( fl-hydroxyethyl) -2- gamma-tetradecyl amino) -2-imidazoline, 1-( fl-hydroxycthyl) -2-(gamma-hexadecy1 amino)- Z-imidazoline and l fi-hydroxyethyl -2- gamma-tetracosyl amino)-2-imidazoline as typical higher compounds.

The present imidazoline compounds are prepared by contacting the alkylamine, which it is desired to have present in the final compound with 1'-(,8-hydroxyethyl)- Z-methylmercapto-Z-imidazoline. The method of prep aration is described in copending application, Serial No. 566,357, now US. Patent No. 2,792,404.

The above imidazoline compounds are well defined stable compounds which range from viscous liquids to waxy or crystalline solids. They are particularly valuable as components of detergent compositions in order to reduce the tarnishing of copper-containing alloys when cutlery articles of such alloys are washed with synthetic detergents.

It is an object of the invention to provide detergent compositions which may be employed in washing soiled cutlery and dishes which remain in contact with the detergent solution for prolonged periods of time. It has been found that cutlery articles, including knives, forks, spoons and other tableware made of German silver and similar copper base alloys, are normally discolored by solutions containing high concentrations of conventional, organic, non-ionic or anionicdeterge'nt compounds. This is commonly observed in the washing of soiled cutlery and other household utensils consisting of copper base alloys, particularly during air-drying, under'which conditions residual amounts of detergent solutions may remain in contact with the cutlery for prolonged periods of time. For example, forks and spoons exhibit tarnishing at those contact points from which the residual solution is evaporated at the conclusion of the washing operation. Plated cutlery made from a base of aCOpper alloy also exhibits this tarnishing if the plating is scratched or thin, and

such tarnishing action may be found on the entire piece of cutlery.

It has now been found that the tarnishing or discoloration efilect upon copper alloys, which is characteristic of non-ionic and anionic synthetic detergent compounds, may be inhibited by the combination therewith of a 1-(;8-hydroxyethyl)-2-gamma-alkyl amino-Z-imidazoline in minor proportions sufiicient to inhibit the said tarnishing. The alkyl radical has from 4 to 24 carbon atoms, and preferably from 14 to 22 carbon atoms. A preferred proportion of this imidazoline employed to reduce discoloration and tarnishing in a detergent composition is from 0.01% to 0.5% by weight based upon the synthetic organic detergent. The mechanism of the inhibitory efiect is not known, but it has been found that relatively small proportions of these compounds are eflective in overcoming the tarnishing efiect of the chemical compounds utilized in detergent compositions. The small proportions of the imidazoline compounds described above are without'eifect on the detergency of the mixture.

The synthetic organic anionic and non-ionic detergent components employed in the present invention include the sulfate andsulfonate type compounds as typical anionic detergents. Representative compounds of the non-ionic type are the others and esters (including sulfur-containing derivatives and analogues) of polyalkylene glycols and polyglycerols. Mixtures of the above detergent components may also be employed.

The aliphatic sulfated or sulfonated detergents which are employed in combination with the imidazoline may have from 8 to 26 carbon atoms. Such-detergents include the aliphatic substituted acyl-containing compounds having an alkyl radical of about 9m 18 carbon atoms, such as the aliphatic carboxylic ester detergents. Examples of aliphatic anionic detergents are the sulfuric acid esters of polyhydric alcohols incompletely esterified with higher fatty acids, for example, cocoanut oil mono-gly ceride mono-sulfate, tallow diglyceride monosulfate, the long-chain pure or mixed higher, primary and secondary alkyl sulfates, such -as lauryl sulfate, cetyl sulfate, and higher fatty acid alcohol sulfates derived from reduced cocoanut oil fatty acids. Other detergent compounds which may be used in combination with the l-(B-hydroxyethy1)-2-( gamma-alkyl amino)-2-i1nidazoline include the hydroxy sulfonated higher fatty esters, for example, the.

higher fatty acid esters of 2,3-dihydroxy propane sulfonic acid, and the higher fatty esters of low molecular Weight alkylol sulfonic acids, such as the oleic, ester of isethionic acid. The invention also contemplates the use of higher fatty ethanolamide sulfates, the higher fatty acid amides of amino alkyl sulfonic acids, for example lauric amide of taurine, etc. The salts of thevarious compounds employed in the present invention are preferably the sodium, ammonium or potassium salts.

One of the preferred types of detergent components is a sodium or ammonium sulfonate of an alkyl-substituted aromatic hydrocarbon selected from the group consisting of benzene, toluene and xylene, wherein the alkyl group has from 9 to 18 carbon atoms. The said alkylaryl hydrocarbon is sulfonated and is then neutralized with a sodium, potassium or ammonium alkaline compound to obtain the corresponding sodium, potassium,-

alkanolammonium or ammonium salt. In the preparation of the alkylaryl sulfonate, the alkyl group is preferably of about 9 to 18 carbon atoms average length, such as may be obtained from olefins or from kerosene. The kerosene may be chlorinated and the aromatic compound alkylated therewith in known manner. Compounds of the sulfonate type are described in US. Patents 2,232,- 117 and 2,232,118. to Kyrides. A preferred compound of this type is sodium dodecyl benzene sulfonate, also Patented June 5, 1962 3 known as sodium tetrapropyl benzene sulfonate when derived from tetrapropylene and benzene.

Other compounds of the above category of anionic detergents having utility in the present invention include the sulfa-ted esters such as the sulfated esters of succinic acid and of sulfophthalic acid. Examples of such compounds which may be employed in the present detergent compositions are the sodium salt of dioctyl sulfosuccinate, sodium hexyl-4-sulfophthalate and octadecyl sulfophthalate. The present invention may also employ sulfonates of an acid which is esterified with a monohydric alcohol. A salt of this type of compound is sodium tridecyl fl-sulfopropionate.

Another group of useful detergent compounds are the sulfated and sulfonated anionic detergents based on alkyl phenols of long chain, fatty alcohols and tall oil condensed with ethylene oxide or propylene oxide. Examples of such compounds are the sodium, ammonium or amine (e.g., triethanolamine) salts of nonyl phenol condensed with ten moles of ethylene oxide and then sul fated, while another useful compound is tridecanol which has been condensed with ten moles of ethylene oxide and then sulfated.

The anionic detergents are generally employed in the form of water-soluble salts, such as the alkali metal salts described above. However, the alkaline earth metal, ammonium, amine, and alkylolamine salts are likewise of utility in the present invention. While the sodium, potassium, ammonium and alkylolarnine (e.g., mono-, diand triethanolamine) salts are ordinarily preferred, other salts such as the lithium and magnesium salts may be used if desired. For certain purposes, as for example where it is desired to attain the maximum solubility, the ammonium and alkylolamine salts are preferred.

The non-ionic compounds which are employed in the present invention include the polyoxyethylene ethers of aliphatic alcohols having straight and branched chain configurations. Long chain derivatives of polyhydroxy compounds such as the ethers of polyalkylene glycols may also be employed in the present detergent compositions. Other compounds include the polyoxyethylene ethers of alkyl aromatic hydroxy compounds, for example, the alkylated polyoxyethylene phenols.

A typical compound of this group is the ethylene oxide condensation product of a highly branched monohydric primary alcohol such as tridecanol, having the molecular configuration of an alcohol produced by the x0 process from an olefin such as triisobutylene or tetrapropylene, with from 1 to 20 moles of ethylene oxide per mole of alcohol. A preferred range is from 5 to moles of ethylene oxide. The present invention includes the use of a mixture of isomeric monohydric primary tridecyl alcohols, said alcohols being derived from the Oxo process carried out with a material of the class consisting of polybutylenes and polypropylenes.

Another detergent component of the polyoxyethylene condensate type is the product obtained by the condensation of tall oil with ethylene oxide. The condensation of tall oil with ethylene oxide may be conducted with from 1 to 20 moles of ethylene oxide per mole of the tall oil, a preferred range being from 5 to moles of ethylene oxide. Another condensation product of this type which is useful in the present invention is the product resulting from the condensation of tertiary octyl or nonyl phenyl with from 5 to moles of ethylene oxide per mole of the said phenol.

Polyoxyethylene compounds containing sulfur are also of utility. A compound of this type which may be employed in the present invention is the condensation product of a tertiary mercaptan having from 6 to 20 carbon atoms, condensed withfrom 5 to 20 moles of ethylene oxide per mole of mercaptan.

The above described polyalkylene condensation products may be prepared from propylene oxide as well as 4 with ethylene oxide. Admixtures of these two condensing agents may also be employed.

Another synthetic, organic detergent component which may be employed in the present invention is a compound selected from the group of alkanolamides of fatty acids, preferably having from 10 to 20 carbon atoms. A preferred compound of this type is lauric diethanolamide derived from diethanolamine and crude lauric acid. Other acids and mixtures thereof may similarly be employed for this purpose. For example, an alkanolamide may be prepared from the fatty acids derived from tall oil during the purification and fractionation thereof. The alkanolarnine which is employed to form the preferred alkylolamides may be monoor diethanolamine, mono or diisopropanolamine, or monoor di-n-propanolarnine. Preferred amines are diethanolamine and monoethanolamine.

Other sources of fatty acids which may be used in the preparation of the alkylolamides are the naturally occurring fatty acids, such as those derived from cocoanut oil. The said cocoanut oil fatty acids are within the present preferred group of fatty acids having from 10 to 20 carbon atoms in the acid radical.

In addition to the above-described synthetic, organic detergent components, the present compositions may include builders such as inorganic phosphate and sulfate salts. The preferred amounts of builders are from 99 to 20 parts by weight of the inorganic 'builder, the balance to make 100 parts consisting of the synthetic, organic detergent.

The present invention contemplates the formulation of detergent compositions including a variety of polyphosphates, preferred compounds being selected from the group consisting of tripolyphosphates, pyrophosphates, hexametaphosphates, tetrap'hosphates, and mixtures thereof. The sodium and ammonium salts are ordinarily employed, but the potassium salts may similarly be employed, particularly in the formulation of liquid detergent concentrates. Other inorganic salts such as the sodium silicates may also be utilized in the compositions of the present invention.

methyl cellulose are likewise contemplated Within the scope of the invention.

The present invention also includes liquid formulations which may contain from 30% to 75%, and preferably from 40% to 65% by weight of water based upon the total liquid detergent. Alcohols such as ethanol, and glycols such as ethylene glycol may also be present to improve solubility of the various components. The proportion of alcohol or glycol may be from 1% to 20% by weight of the mixture.

The following specific examples further illustrate the present invention.

A detergent composition consisting of a solution of the following ingredients was prepared, the proportions being based on the weights of the respective components. This table also sets forth the preferred range of proportions of the respective components:

Specific Range, Example, percent;

percent Ammonium lauryl sulfate 10. 8 5-25 10.4 5-25 16.5 625 2.3 0. 5-25 13.7 025 46.1 84.6-30 l-(B-hydroxyethyl) -2 -(gamma-octadecyl amino)-2-imidazollne 0.20 0.03-1 5 water to 0.20 Weight percent concentration and tested Detergent builders and modifiers, for example, sodium sulfate, fluorescent dyes, perfume and carboxyf as described below in order to determine the relative efiectiveness of the contained tarnish inhibitor. The tests were conducted upon small samples of German silver which had been first polished with crocus cloth and then washed and rinsed in acetone. The metal test samples were exposed in a half submerged position in a beaker containing the respective detergent composition solution.

The exposure was continued for a period of 24 hours at a temperature of approximately 70 F. At the conclusion of this time the metal samples were removed and examined to determine the extent of the discoloration. The rating system used was based on a visual examination employing the following scale of values:

None.

1Very slight corrosion at air-solution interface only. 2Slight, at air-solution interface only. 3--Considerable.

4-Severe.

A number of additional related compounds were included in the test. The test data are summarized below:

Discoloration Discoloration Inhibitor: Rating 1- (fl-hydroxyethyl) -2- gamma-butylamino) -2- imidazoline 2 1- (,B-hydroxyethyl) -2- gamma-tetradecylamino Z-imidazoline lp-hydroxyethyl) -2- gamma-hexadecylamino) 2-imidazoline 2 1- ,B-hydroxyetbyl) -2- (gamma-octadecylamino) 2-imidazoline 0 1- fl-hydroxyethyl -2- (gamma-dodecylamino) -2- imidazoline 2 Built detergent composition without inhibitors--- 4 Distilled water only (without detergent) 4 The above data indicate that the combination of a 1-(13- hydroxyethyl) 2 (gamma alkyl amino) 2 imidazoline, together with a synthetic, organic detergent composition resists the tarnishing eifect which is otherwise characteristic of the detergent composition employed pound of the anionic or non-ionic type, together with a minor proportion of 1-( e-hydroxyethyl)-2-( gamma-alkylamino)-2-imidazoline to resist tarnishing of copper base alloys by the said detergent compound.

What is claimed is:

1. A detergent composition essentially consisting of a synthetic, organic detergent selected from the group consisting of anionic and non-ionic detergent which normally tarnish copper base alloy-s and in combination therewith an amount of a 1-(fl-hydroxyethyl)-2-( gamma-alkylamino)-2-imidazo1ine in which the alkyl radical has from 4 to 24 carbon atoms sufficient to inhibit tarnishing of the copper base alloy.

2. A detergent composition essentially consisting of a synthetic, organic detergent selected from the group consisting of anionic and non-ionic detergents which normally tarnish copper base alloys and in combination therewith a small amount of 1-(B-hydroxyethyl)-2-(gammaoctadecylamino) -2-imidazo1ine sufficient to inhibit tarnishing of the copper base alloy.

3. A detergent composition essentially consisting of a synthetic, organic detergent selected from the group consisting anionic and non-i onic detergents which normally tarnish copper base alloys and in combination therewith a small amount of l-(B-hydroxyethyl)-2-(gam-V ma-butylamino) -2-imidazoline sufficient to inhibit tarnish ing of the copper base alloy.

4. A detergent composi 'on essentially consisting of a synthetic, organic detergent selected from the group consisting of anionic and non-ionic detergents which normally tarnish copper base alloys and in combination therewith a small amount of l-(fi-hydroxyethyl)-2-(gammatetradecylamino)-2-imidazoline suflicient to inhibit tarnishing of the copper base alloy.

5. A detergent composition essentially consisting of a synthetic, organic detergent selected from the group consisting of anionic and non-ionic detergents which normally tarnish copper base alloys and in combination therewith a small amount of l-(fi-hydroxyethyl)-2-(gammahexadecylamino)2-imidaz0line suflicient to inhibit tarnishing of the copper base alloy.

6. A detergent composition essentially consisting of a synthetic, organic detergent selected from the group consis-ting of anionic and non-ionic detergent which normally tarnish copper base alloys and in combination therewith a small amount of I-(fi-hydroxyethyl)-2-(gammadodecylamino)-2-imidazoline sufiicient to inhibit tarnishing of the copper base alloy.

7. The method of washing cutlery made of a copper base alloy which comprises subjecting said cutlery to an aqueous solution of a detergent composition essentially consisting of a synthetic, organic detergent selected from the group consisting of anionic and non-ionic detergents which normally tarnish said cutlery, and in combination therewith about 0.01% to 0.5% by weight based upon the said detergent of 1-( ,B-hydroxyethyl)2( gamma-alkylamino)-2-irnidazoline in which the alkyl radical has from 4 to 24 carbon atoms to inhibit tarnishing of the said cutlery.

8. The method of washing cutlery made of a copper base alloy which comprises subjecting said cutlery to an aqueous solution of a detergent composition essentially consisting of a synthetic, of organic detergent selected from the group consisting of anionic and non-ionic detergents which normally tarnish said cutlery, and in combutylamino)-2-imidazoline to inhibit tarnishing of thesaid cutlery.

10. The method of washing cutlery made of a copper base alloy which comprises subjecting said cutlery to an aqueous solution of a detergent composition essentially consisting of a synthetic, organic detergent selected from the group consisting of anionic and non-ionic detergents which normally tarnish said cutlery, and in combination therewith about 0.01% to 0.5% by weight based upon the said detergent of 1(e-hydroxyethyl)-2-(gamma-tetradecylamino) -2-imidazoline to inhibit tarnishing of the said cutlery,

11. The method of washing cutlery made of a copper base alloy which comprises subjecting said cutlery to an aqueous solution of a detergent composition essentially consisting of a synthetic, organic detergent selected from the group consisting of anionic and non-ionic detergents which normally tarnish said cutlery, and in combination therewith about 0.01% to 0.5 by weight based upon the said detergent of 1- (B-hydroxyethyl)-2-(gamma-hexacylamino)-2-imidazoline to inhibit tarnishing of the said cutlery.

References Cited in the file of this patent the said detergent of l-(B-hydroxyethyD-Z-(gamma-dode- 10 ,7

UNITED STATES PATENTS Schaefier Nov. 18, 1952 Schaeffer Nov. 18, 1952 Ruff Jan. 31, 1956 Garmaise May 14, 1957 

1. A DETERGENT COMPOSITION ESSENTIALLY CONSISTING OF A SYNTHETIC, ORGANIC DETERGENT SELECTED FROM THE GROUP CONSISTING OF ANIONIC AND NON-IONIC DETERGENT WHICH NORMALLY TARNISH COPPER BASE ALLOYS AND IN COMBINATION THEREWITH AN AMOUNT OF A 1-(B-HYDROXYETHYL)-2-(GAMMA-ALKYLAMINO)-2-IMIDAZOLINE IN WHICH THE ALKYL RADICAL HAS FROM 4 TO 24 CARBON ATOMS SUFICIENT TO INHIBIT TARNISHING OF THE COPPER BASE ALLOY. 